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<h2><a name="SECTION0018110000000000000000"></a><a name="posix-large-files"></a>
<br>
16.1.1 Large File Support 
</h2>

<a id='l2h-3514' xml:id='l2h-3514'></a>

<p>
Several operating systems (including AIX, HPUX, Irix and Solaris)
provide support for files that are larger than 2 Gb from a C
programming model where <tt class="ctype">int</tt> and <tt class="ctype">long</tt> are 32-bit
values. This is typically accomplished by defining the relevant size
and offset types as 64-bit values. Such files are sometimes referred
to as <i class="dfn">large files</i>.

<p>
Large file support is enabled in Python when the size of an
<tt class="ctype">off_t</tt> is larger than a <tt class="ctype">long</tt> and the <tt class="ctype">long long</tt>
type is available and is at least as large as an <tt class="ctype">off_t</tt>. Python
longs are then used to represent file sizes, offsets and other values
that can exceed the range of a Python int. It may be necessary to
configure and compile Python with certain compiler flags to enable
this mode. For example, it is enabled by default with recent versions
of Irix, but with Solaris 2.6 and 2.7 you need to do something like:

<p>
<div class="verbatim"><pre>
CFLAGS="`getconf LFS_CFLAGS`" OPT="-g -O2 $CFLAGS" \
        ./configure
</pre></div> 
<p>
On large-file-capable Linux systems, this might work:

<p>
<div class="verbatim"><pre>
CFLAGS='-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64' OPT="-g -O2 $CFLAGS" \
        ./configure
</pre></div> 
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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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